With a brain the size of a salt grain, a fruit fly can do Top Gun maneuvers in about one-fiftieth of the time it takes to blink a human eye.

That a fruit fly manages to do fighter-jet banked turns in midair contradicts some earlier ideas about how tiny insects maneuver, says Michael Dickinson of the University of Washington in Seattle. Other researchers had suggested that turning flies “use their wings almost like paddles to sort of row themselves around,” he says. Yet an elabora...